President Recep Tayyip Erdogan on Wednesday indicated that Turkey went ahead with the purchase of Russia’s S-400 missile system because it was tired of waiting for another supplier. Anadolu Agency said. The deal has caused concern among Turkey’s NATO allies as the Russian air defense system is incompatible with the air defenses of other NATO members. “They went crazy just because we made the S-400 deal،” Erdogan told a meeting of city mayors from his ruling party in Ankara. “What are we supposed to do? Wait for you? We are taking security measures and will continue to do so.” Earlier this week، Erdogan said the first payment for the S-400 had been made. The total value of the deal is believed to be around $2.5 billion. Vladimir Kojin، an aide to Russian President Vladimir Putin، confirmed on Tuesday that a contract had been signed. “I can merely guarantee that all of the decisions made under this contract strictly agree with our strategic interests،” he told the TASS news agency. The compatibility of the S-400 system is the main concern of NATO.